A case of supernumerary muscle bundle “M. tubero-femoralis fick” of the beceps femoris in a crab-eating monkey

A supernumerary muscle bundle “M. tubero-femoralis Fick” of the biceps femoris was found in a female crab-eating monkey in both hindlimbs.     

Contribution from the chirality of the growing chain to the enantiomer selectivity in activated-NCA polymerization of α-amino acid N-carboxyanhydride

As a model compound for the growing chain in the activated-NCA type of polymerization of α-amino acid N-carboxyanhydride (NCA), 3-[ω-acetylglycyl-poly(α-amino acid) acyl]-α-amino acid NCA (called the prepolymer) having various degrees of polymerization (DPs) was synthesized by the polymerization of Phe, Val, Glu(OEt), and Asp(OBzl) NCA in the presence of AcGly NCA by the tertiary amine. Activated (S)-Phe, Val, Glu(OEt), and Asp(OBzl) NCA were added to the terminal cyclic group of the corresponding (S)- or (R)- prepolymer, and the enantiomer selectivity in the reaction was investigated. With prepolymers having DPs ranging from 1 to 15, the addition reaction always took place preferentially between species having the same configuration, and the degree of the enantiomer selection increased with increasing DP of the prepolymer. With prepolymers having DP = 1 and 2, we found contributions from the chiral terminal unit and the chiral penultimate unit to the enantiomer selection, respectively. Prepolymer having DP = 5 was shown to take a β-type conformation, which led to higher enantiomer selection; and prepolymers having DP = 10 and 15 were shown to take an α-helix conformation, which led to much higher enantiomer selection than did the β-type conformation. In the present investigation the mechanisms of terminal-unit control, penultimate-unit control and conformational control of the enantiomer selection in the activated-NCA type of polymerization were clearly observed.     

Confirmation of the human thymidine kinase locus, 17q21 → 17qter,by means of a man-mouse somatic cell hybrid,D98/AH-2 X LMTK−Cl-1D

Summary A large metacentric marker chromosome, m20, in a line of human D98/AH-2 cells was identified by Q bands as being a translocation (1;17)(p36;q21). This was confirmed by means of somatic cell hybridization between D98/AH-2 and thymidine kinase (TK) deficient mouse cells. The hybrid clones by HAT selective system retained m20, indicating the presence of TK locus on this chromosome. The results also provide evidence that TK gene is located on the distal region of the breakpoint in 17q21 but not on 17q21 17pter.     

Development of microbodies in Candida tropicalis during incubation in a n-alkane medium

Development of microbodies in Candida tropicalis pK 233 was studied mainly by electron microscopical observation. The yeast cells, precultured on malt extract, scarcely contained microbodies and showed very low catalase activity. When the precultured cells were transferred to a n-alkane medium and incubated with shaking, the number of microbodies increased and concomitantly the activity of catalase was enhanced. That is, both the area ratio of microbodies in the cell and the ratio of microbodies to cytoplasm in area increased significantly during the utilization of n-alkanes for 8 hrs. Localization of catalase in the microbodies was demonstrated cytochemically by use of 3,3'-diaminobenzidine, but other organella in the cell, except for vacuoles appearing in the early growth phase and mitochondria, were not stained with this reagent. Microbodies seemed to grow by division. Biogenesis of microbodies in the yeast cells is also discussed.     

A monoclonal antibody distinguishes growth cartilage from other types of cartilage: a new probe for osteogenic cartilage

Summary Monoclonal antibodies (mAbs) were raised by injection of a homogenate of cultured growth cartilage (GC) cells from young rabbit ribs. These mAbs were examined by immunohistochemical staining for their reactivity to paraffin sections of rabbit tissues. The results showed that an mAb reacted preferentially with late hypertrophic and calcified costal GC zones. The mAb also reacted with hypertrophic GC adjacent to bone that existed in sternum and femur, but not to other cartilages, including resting cartilage, articular cartilage, auricular cartilage, nasal cartilage, tracheal cartilage and meniscus cartilage, or with other tissues, including tendon, skin, muscles, lung, liver, heart, thymus, spleen, eye and gut. It reacted with a wider area of the GC zone when the sections were decalcified, although its reactivity with the extended area was much less intensive than that with late hypertrophic and calcified GC zones. On treatment of the sections with bacterial collagenase, neither the reactive area nor its intensity were changed, while when treated with trypsin the reactivity was lost.These results suggest the existence of a certain molecule which distinguishes GC (osteogenic cartilage) from other (non-osteogenic) cartilage. This mAb is a useful probe for distinguishing osteogenic cartilage from non-osteogenic cartilage, and for studying differentiation steps of cartilage cells in endochondral bone formation. The mAb can also be used as a probe for clinical and stored specimens because it reacts with decalcified and paraffin-embedded human specimens.     

Biodegradation of poly(l-lactide)

The biodegradation of poly(L-lactide) (PLA) is reviewed. The important role of actinomycetes in PLA degradation is emphasized. These PLA-degrading actinomycetes belong phylogenetically to the Pseudonocardiaceae family and related genera, including Amycolatopsis, Lentzea, Streptoalloteichus, Kibdelosporangium and Saccharothrix. A PLA-degrading enzyme purified from an isolated Amycolatopsis strain-41 has substrate specificity on PLA higher than proteinase K. The application of these strains and their enzymes can be effectively used for biological treatment of plastic wastes containing PLA.     

Effects of Amyloid β-Peptides and Gangliosides on Mouse Neural Stem Cells

The interaction of amyloid β-proteins (Aβs) with membrane lipids has been postulated as an early event in Aβ fibril formation in Alzheimer’s disease. We evaluated the effects of several putative bioactive Aβs and gangliosides on neural stem cells (NSCs) isolated from embryonic mouse brains or the subventricular zone of adult mouse brains. Incubation of the isolated NSCs with soluble Aβ1–40 alone did not cause any change in the number of NSCs, but soluble Aβ1–42 increased their number. Aggregated Aβ1–40 and Aβ1–42 increased the number of NSCs but soluble and aggregated Aβ25–35 decreased the number. Soluble Aβ1–40 and Aβ1–42 did not affect the number of apoptotic cells but aggregated Aβ1–40 and Aβ1–42 did. When NSCs were treated with a combination of GM1 or GD3 and soluble Aβ1–42, cell proliferation was enhanced, indicating that both GM1 and GD3 as well as Aβs are involved in promoting cell proliferation and survival of NSCs. These observations suggest the potential of beneficial effects of using gangliosides and Aβs for promoting NSC proliferation.     

Membranous Structure of Purified Escherichia coli Lipopolysaccharide

The ultrastructure of the purified and lyophilized endotoxin from Escherichia coli O111 was observed by ultrathin sectioning. Onion-like globular membrane structures were observed in addition to rod-like and ribbon-like structures, indicating the existence of a globular membrane structure even in the dried state.     

Effects of vitamin D3 on signaling by prostaglandin E2 in osteoblast-like cells

We investigated the effects of vitamin D₃ on the signaling pathways by prostaglandin E₂ (PGE₂) in osteoblast-like MC3T3-E1 cells. The pretreatment with 1,25-dihydroxyvitamin D₃ (1,25-(OH)₂D₃), an active form of vitamin D₃, significantly inhibited cAMP accumulation induced by 10 μM PGE₂ in a dose-dependent manner in the range between 1 pM and 1 nM. This effect of 1,25-(OH)₂D₃ was dependent on the time of pretreatment up to 8 h. 1,25-(OH)₂D₃ also inhibited the cAMP accumulation induced by NaF, a GTP-binding protein activator, or forskolin which directly activates adenylate cyclase. On the other hand, 1,25-(OH)₂D₃ significantly inhibited PGE₂-induced IP₃ formation in a dose-dependent manner between 10 pM and 1 nM. However, 1,25-(OH)₂D₃ had little effect on NaF-induced IP₃ formation. The pretreatment with 24,25-dihydroxyvitamin D₃, an inactive form of vitamin D₃, affected neither cAMP accumulation nor IP₃ formation induced by PGE₂. These results strongly suggest that 1,25-(OH)₂D₃ modulates the signaling by PGE₂ in osteoblast-like cells as follows: the inhibitory effect on the cAMP production is exerted at a point downstream from adenylate cyclase and the inhibitory effect on the phosphoinositide hydrolysis is exerted at the point between the PGE₂ receptor and GTP-binding protein, probably G_i2.